Facebook Login Activity

FacebookLoginActivity.java

import android.accounts.Account;
import android.accounts.AccountManager;
import android.content.Intent;
import android.os.Bundle;
import android.util.Log;
import android.widget.TextView;
import com.facebook.AppEventsLogger;
import com.facebook.Session;
import com.facebook.SessionState;
import com.facebook.UiLifecycleHelper;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;

public class FacebookLoginActivityNew extends Activity {

	private static final int REAUTH_ACTIVITY_CODE = 100;
	private static final List<String> PUBLISH_PERMISSIONS = Arrays
			.asList("publish_actions");
	private static final List<String> READ_PERMISSIONS = Arrays
			.asList("email");
	private static final String TAG = "FacebookLoginActivity";
	private UiLifecycleHelper lifecycleHelper;

	@Override
	public void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		
		lifecycleHelper = new UiLifecycleHelper(this, new Session.StatusCallback() {
			@Override
			public void call(Session session, SessionState state, Exception exception) {
				onSessionStateChanged(session, state, exception);
			}
		});
		lifecycleHelper.onCreate(savedInstanceState);

		ensureOpenSession();
	}

	@Override
	protected void onStart() {
		super.onStart();
		// Update the display every time we are started.
	}

	@Override
	protected void onResume() {
		super.onResume();
		// Call the 'activateApp' method to log an app event for use in analytics and advertising reporting.  Do so in
		// the onResume methods of the primary Activities that an app may be launched into.
		AppEventsLogger.activateApp(this);
	}

	public void onActivityResult(int requestCode, int resultCode, Intent data) {
		Session.getActiveSession().onActivityResult(this, requestCode, resultCode, data);

		switch (requestCode) {
			case REAUTH_ACTIVITY_CODE:

				Session session = Session.getActiveSession();
				if (session != null) {
					onSessionStateChanged(session, session.getState(), null);
				}
				break;
		}
	}

	private boolean ensureOpenSession() {
		if (Session.getActiveSession() == null ||
				!Session.getActiveSession().isOpened()) {
			Session.openActiveSession(this, true, READ_PERMISSIONS, new Session.StatusCallback() {
				@Override
				public void call(Session session, SessionState state, Exception exception) {
					onSessionStateChanged(session, state, exception);
				}
			});
			return false;
		}
		return true;
	}

	private boolean sessionHasNecessaryPerms(Session session) {
		if (session != null && session.getPermissions() != null) {
			for (String requestedPerm : PUBLISH_PERMISSIONS) {
				if (!session.getPermissions().contains(requestedPerm)) {
					return false;
				}
			}
			return true;
		}
		return false;
	}

	private List<String> getMissingPermissions(Session session) {
		List<String> missingPerms = new ArrayList<String>(PUBLISH_PERMISSIONS);
		if (session != null && session.getPermissions() != null) {
			for (String requestedPerm : PUBLISH_PERMISSIONS) {
				if (session.getPermissions().contains(requestedPerm)) {
					missingPerms.remove(requestedPerm);
				}
			}
		}
		return missingPerms;
	}

	private void onSessionStateChanged(final Session session, SessionState state,
	                                   Exception exception) {
		if (state.isOpened() && !sessionHasNecessaryPerms(session)) {
			requestPublishPermissions(session);
		} else if (state.isOpened()) {
			finishFacebookLogin(session);
		}
	}

	private void requestPublishPermissions(Session session) {
		if (session != null) {
			Session.NewPermissionsRequest newPermissionsRequest = new Session.NewPermissionsRequest(
					this,getMissingPermissions(session));

			newPermissionsRequest.setRequestCode(REAUTH_ACTIVITY_CODE);
			Session mSession = Session.openActiveSessionFromCache(this);
			mSession.requestNewPublishPermissions(newPermissionsRequest);
		}
	}

	private void finishFacebookLogin(Session session) {
		if (ensureOpenSession()) {
			Log.d(TAG, "Facebook permissions complete");
		}
	}
}